Telemetric apparatus



Aug. 10, 1943.

TRANSMITTER LEVEL FEET F. B. BRISTOL 2,326,200

TELEMETRIC APPARATUS Filed Jan. s, 1941 2 Sheets-Sheet; 1

CONTROL BOX UNATTENDED STATION EXEHANGE RELAY FIG. I

8 IO I2 l4 I6 I8 20 22 24 SECONDS IN VEN TOR.

DURATION OI SIGNALB F a 3.3 e

1943- F. B. BRISTOL V ,32

TELEMETRIC APPARATUS- Filed Jan. 8, 1941 2 Sheets-Sheet 2.

I nos CONTROL 7 BOX I I2 UNATTENDED A RECEWER I STATION us I CONTROL BOX -INVENTOR.

Patented Aug '10, 1943 UNITED sTA'res PATENT porno-s *wmm filmuvs, I

Franklin B. Bristol, Middlebury, Conn., assignor to The "Bristol Company, Waterbury, Conn a corporation of Connecticut v Application January 8, 1941, Serial No. 373,617

Claims. (cum-351) This invention relates to telemetering systems, and more especially to that class of tele-' metering systems in which 'a measurement of a magnitude performed at one station is translated into audible code signals, transmitted over a communication channel of a conventional type, and at, a receiving station expressed as ascalar magnitude determined by characteristics of said signals.

In the art of telemetering there is recognized the practice of transmitting over a communication system signals initiated. by contacts forming a part of a continuousdisplacement meter, such as a current meter or anemometer, and, by timing the spacing of these signals as received, de-' termining the rate of '.flow as measured at the transmitting point. There is also recognized a method whereby a variable magnitude, such as liquid level ata transmitting station, is caused to control the nature of codesignals, which, at the receiving station, may be interpreted in terms of said code, therebyproviding a discontinuous measure of the desired magnitude.

Both these systems have been developed in forms adaptable to conventional communication systems, such as long-distance telephone lines and'exchanges, whereby, by the simple expedient of dialing or otherwise calling a number representing the transmitting station, connectionmay be made with the signaling apparatus and the desired measurement obtained.

It is an object of this" invention .to provide' and representing a corresponding number of measurable magnitudes, and at the receiving end of the system indicated. or recorded as separate and independent measurements.

Other features and advantages oi the invention will be hereinafterdescribed and claimed.

In the accompanying drawings: n Fig. 1 is a diagrammatic representation of a telemetering system embodying the principles of the invention. v i

Figs. 2 and 3 are representations of a modified form of receiving apparatus therefor.

- of atransm'itting instrument I0, 5. receiving instrument II and interconnecting apparatus including a control box l2. an automatic unattended station l3, a conventional telephone exchange I4, an interconnecting circuit orchannel l5, and

a local circuit I6. At the receiving station is a telephone 'set ll of the standard type. The

means whereby a normally inert automatic signaling apparatus which may be operatively associated with any one oi a variety'of measuring elements may be made subject to operation by 'telephone apparatus of conventional-types, and,

upon the establishment of a communication channel therethrough, caused to operate for a predetermined limited time, sufiicientto transmit a number of, complete impulse gro ups o'r sig+ nals, after which operation automatically ceases, and the apparatus is cleared from the line.

A further object of the invention'lfes in the provision of means by which said impulses as audibly received at the home station mayreadily be expressed as a continuous scalar representation of the measurement performed at'thetransmitting station. I 7

A further object of the invention is found in the provision of means whereby, without any modification in electrical circuits or apparatus; the system may be made responsive to two or more simultaneous sets of impulses or signals developed by as many transmitting instruments 5 seen in the drawings. The scroll-plate 2'l has an transmitting instrument Ill is here shown as adapted to the purpose .of water level' determination as measured by the position of a float l8 resting on the surface of a body of water l9 whose level it isdesired to determine and transmit quantitatively to the receiving instrument I I. The float I8 is associated with the transmit ting instrument I0 through the medium of a cable 20' passing over a pulley 2| attached to the instrument and counter-balanced by a weight 22. Secured to the shaft of the pulley 2| is a pinion,

23 rotatable with the pulley and meshing with a gear sector 24 mounted upon a rotatable axis or. spindle -25. Attached to the spindle 25 is a pointer-arm 26 adapted to deflect through a limited angle with movement of the gear sector 24, whereby the position of said pointer-arm be-' comes an indication of th'liquid level'which it is desired to measure. The mechanism of the transmitting instrument l0 may be. similar in all respects'to that fully set forth and described in-U. 8. Letters Patent 2,214,159 issued Septemvice a scroll-plate 21 is driven by a motor 28 and caused to rotate about an axis 28 at a constant angular velocity in a counter-clockwise sense as iarcuate leading edge and a spiral trailing edge inla sense perpendlcularto its normal plane of deflection periodically with the rotation of the scroll-plate. (Fixed to a shaft till journaled for rotation through a limited angle about an axis parallel to the planeof rotation of the scrollplate El is a'rooker-plate 3i juxtaposed to the extremity of the pointer-arm 243 in such a manner that, as said pointer is periodically displaced by rotation of the scroll-plate 2i, said rocker-plate will be deflected through a short distance causing the shaft 35 to be rotated in a corresponding manner. Carried by the shaft so is an arm 32 bearing a member stadapted to close or open an electric contact 3% according as to whether the pointer-arm 23 is, or is not, displaced by the scroll-plate 2?. By reierenceto the said Bristol patent it will be seen that the member 33 may thus be used to control a. circuit which includes contact iii in such a manner that there will be imposed on said circuit cyclically recurrent inipulses of durations dependent upon the deflection of the pointer-arm 2b, and therefore of the position of the float l8. p I The control box it includes a single-throw, double-pole relay 8t, aoam-actuated-contactor 3i and a buzzer, bowler, or other, device, 32 suitable to the production oi an audible tone upon energization from a source of electrical power.

The relay t e-is oi the double-pole class, arranged when energized to close two independent sets of contacts 39 and I includes two electrically independent contact'elements ii and t2, and a earn rneniherdil arranged to be driven at a constant speed-Coya motor is. The periphery of the cam member is provided with a notch a dwell embracing a large proportion cl its circwmference, and .a short lift ll, these several elements of the periphery operatively engaging a follower 5.2! whereby the contact elements 5i and will be operated in a sense that when the follower rests in the notch 35 both contacts will he opened, when the follower engages the dwell contacts ll will be closed and i2 open, and when the follower engages the lift ill both sets of contacts will be closed. The buzzer or howler 38 may be mounted upon the control box it, or located within it in such a enthat the sound produced thereby when energized may be distinctly audible out- 1, side the box. For purposes of insulation, it is generally expedient that there be included in the control box a'small transformer 69 adaptedwhen energized from a commercial A. C. supply source to to provide a supply of power suitable to the operation of the several operating circuits of the system, while providing complete isolation between said circuits and the source of supply.

The unattended station it! is shown diagrammatically in a form greatly simplified in comparison with such stations when in actual use.-

Here all functions except those desirable for carryingout the functions of the invention, and the apparatus for performing those functions, have been eliminated from the drawings. The station in its simplified form includes afour-pol relayti, a'single-pole low-frequency A. C. relay having in series therewith a capacitor 553, a microphone 5d, an audio frequency transformer 55, and such batteries and connections as will now be set'forth. The relay 5i serves, when enerv gized, to-close four sets of contacts to, 571, 68 and 1 9. The relay 52 is of a type adapted to ener- The contact-or 31 gization from the "ringing current commonly usedior signalling in telephone circuits, and acts to close contacts to when energized. In series with the winding of relay 52 is the capacitor 5 53 adapted to pass current of ringing frequency to energize the relay but to prevent the flow'of direct current through the circuit of said relay. The microphone '56, which is placed ina position where it will pick up; sound waves emanating from thebuzzer 83 is energized from a battery 62 in series with the'prinzary of'the transformer 55 and the contacts 59 on the relay v I The internal and interconnecting circuits of the control box 82 and'the unattendedstation liif le er-re as follows: One terminal of the secondary or the transformer 69 is connected by means of a conductor 555 to a corresponding terminal of the motor 2d, the motor i l, the buzzer 88, and one side of the contact li. The other terminal goof the econdary of the transformer is connected by means or a conductor to one side of the energizing winding of the relay 35 and to one side of each of thecontacts 3d and ill). The other side or the contact 39 is connected through a conductor P55 to the free terminals oi the motors and :38. The free side of the contact id is connected by'means or a conductor to to the contact 3d, and thence through a conductor ill to the free terminal or the buzzer 3B. The free terminals oi the winding oi the relay and the contact respectively are connected together by rneans of a conductor The communication channel it enters the'unattended station it as two conductors t9 and it; and the actuating coil or the relay 52 is connected between these conductors in series with the capacitor Contacts on the relay 5i serve to complete, a circuit between the. conductors 59 and in series with the secondary wind-= A0 ing of the transformer One side of the actuating coil of the relay 5i connected through a conduct-or ll to one side of the contact ti] on relay 52, and the other side of said coil through a conductor 72 to a battery l3, and thence by A5 means of a conductor 73 to the other side of contact to. One side of contact 56 of relay 51 is connected to the -:conductor M, and the other side through a resistor it to the conductor ll. Conductors ll and 72 are also connected to the contacts in the control box. Conductors 133 and t8 areccnnected to the two sides of contact 5?, whereby the latter when closed serves ,to bridge or short-circuit the contacts ill in the control box. A telephone set it may be con- 5 ncctedto the line at the transmitting station,

and may be used in the-regular way at any time the telemetering apparatus is not in active oporation.

I The receiving instrument i i may be of the type 0 fully set forth and disclosed in U. SJLetters Patent No. 2,040,918 issued May 19, 1936, to C. W. Bristol, having a constant-speed motor 18, an actuating magnet l9, and an index or pointer 8t adapt-ed to provide in conjunction with a gradc5 mated, scale ti a measure based on the durations of successive cyclical impulses received by the magnet it. A relay 82 of a type adapted to respond to signals in the local circuit is is suitably connected to the telephone ll,and'a circuit 83 provides operative connection between said relay and magnet 119.. The motor 78 in the receiving instrument is energized from a power source 99 which also may supply the circuitof the magnet iii. A double throw single pole switch 9! pro-v videsalternative connection, whereby with the first be assumed. that the system is inert, and

that all parts occupy positions. as shown in the drawing; and that it is desired to obtain atthe telephone set ll. a signal representative of the height of water represented by the position of the float l8. The operator first dials on the telephone I! at the receiving, station, or otherwise calls through the exchange [4, the number corresponding to the unattended station l3 on .the line 55. This will cause a ringing current to flow in the line, which current will pass through the capacitor 53 and operate the relay 52 causing it to close its contacts 60. The closing of the contacts 60 will complete a circuit from the battery 13 through the conductors. and 14 and the winding of the .relay 5!, thus energizing said relay and causing it to close its four sets of contacts. The closing of contacts 56 will serve to bridge the contacts 60 through the resistor 15, so that upon opening of the contacts 60 thereby circuit IE, to the telephone set H where they may be heard by the operator listening at the instrument.

There are several alternative ways by which the signals heard in the telephone set ll may be converted into a definite measurement of-the height of water level as determined by the float I8 at the transmitting station: (a) The operator may listen at the telephone and determine the duration of each periodic signal bymeans of a stop-watch and then by comparison with a graphic chart, such as shown in Fig. 5, may im- .,mediately convert the reading into the units which it is desired to measure; and this may be done without the interposition of any furtherinstruments. (b) The operator may manipulate the switch 9!, throwing it manually to its right presses upon the magnet 19 of the instrument i l 5! will remain locked in by current flowing through said resistor, and will not be released upon de-energization of relay 52 due to cessation of the ringing current.

Closing of the contacts 51 on the relay 5| will represent measured magnitude.

hand position as seen in the drawings each time a signal begins, and opening the switch at the termination of each signal. By this means be ima series of impulses corresponding to those set up at the transmitting station, and will obtain an indication of the pointer 80 of the dial 88 to (c) The operator may throw the switch 9| to its left hand po- .--sition and leave it so long as the signals continue indication on the instrument i I.

serve to complete a circuit from the secondary The cam 43 as driven by the motor 44 in the control box i2, contributes a timing function of a dual natura-limitation of the operating time t of the apparatus upon completion of a call to an Closing of the contacts 39 serves to intercon;

nect the conductors B4 and 65, thus applying the secondary voltage of the transformer 49 to the motors 28 and 44, whereby both these motors are placed in operation; Closing of the'contact Moonnects the conductors 64 and 66, whereby the circuit of the buzzer 38 is made complete with exceptions. of the contact 34, which is subject to actuation by the member carried by the arm 32. Closing of the contacts 58 in the relay 5! serves to short circuit the conductors 69 and I0, thus providing a complete path for voice currents or the equivalent through the unattended station it into the circuit i5. At the same time this interval sufliclent to enable a satisfactory determination to be made without exceeding the time usually allotted for a long distance call, and the bringing of the various elements of the mecha- I the follower 48 out of'the notch 45.onto the dwell action will release the relay 52, and, by means of conventional devices in the exchange l4. will cause the ringing action to cease. Closing of the contacts 59 will provide a complete circuit through the microphone 54, the battery 62 and the primary of the transformer 55, whereby sound.

waves impinging upon the microphone 54 will cause corresponding currents to flow in the circuit i5.

The scroll-platejZ'i, driven by the motor 28 will microphone 54 and will cause a corresponding series of signals to be impressed upon the circuit 15. These signals will pass through the line, and. through the exchange i4, and through the local 46', thus closing the contacts fllbridging the contacts 51 in the Unattended Station, and thus looking the relay 36 in its closedposition without regard to thelposition of the relay 5|, and assuring that the transmitting apparatus will continue to operate, even though the relay 5| should be released. This accomplishes the function of causing the apparatus when .once started to remain in operation until the completion 'of a cycle. The transmitting instrument continues to operlate so long as the follower 48 lies on the dwell 46; and during this interval signals continue to be.

transmitted through the communication chan nel,; and are available at the receiving station.

systems ofthis class, there would thus be allowed ample time for at least five complete sets of im- Pulses to be transmittedpwhlch would positively establish the required measurement, and yet be well witlunithe time'ipterval customarily allowed 7 inal condition.

for long distance telephone calls at the minimum i rate. As the. cam -33 approaches the completion oi?- a single revolution, the lift ll will engage the follower 48, causing the contacts 42 to be closed for a short interval of time, momentarily'conmeeting the conductors ill and i2, and short-cirasaaeoo together with a receiver H5, a microphone 686, a

' relay ill, and a resonator i it. The microphones cuiting the operating winding of the relay el,

whereby the latter is released and opens all its contacts, the resistor l5. limiting dorthe moment the current drawn from the battery it between the instant when the contact or is closed and the ltl and ti l are interconnected and both included in a suitable circuit in .an unattended station -i It at the transmitting ,end of a communication channel are. Each of'the transmitters W5, M2, and associated control'box may be the same as transmitter 29 and control box H2 in Fig. l, and the unattended station its may be the same as station it; it being understood that the control boxes A and B in Fig. amay be connected in instant when the contact as is opened. As the cam it continues its rotation, the follower 88 will drop from the lift at into the notch 35, opening both the contacts 32 and ti. The circuit of the contacts 412 has already been opened by the con-' tact 56. Opening of the contacts it serves to re;

parallel to the contacts of a relay in station H9 similar-to relay til, and that themicrophones i877,

' ft to may be connected in-parallel to a circuit in lease the relay 56, opening in turn the contacts 39 and MB, bringing the motors 28 and 436 to rest, clearing the circuit of the buzzer 3t, and causing all elements of the system to revert to their orig In Fig. 2 is shown caused to operate a receiving instrument of the indicating class. A telephone set. 95 of the con-- ventional type, adapted for calling and answering in the usual manner, is installed at the, receiving station; and a receiving instrument 96, similar in all respects to the instrument in in Fig. 1 is ar amalternative method by, which impulses oi audible frequency may be station Ma similar to that to which microphone 563 is connected in station it. The buzzer or' from box i613. Resonator'iii forming a part of system A is placed between-the telephone set ranged to have its actuating magnet energized through a relay all subject to currents setup-in a microphone es. With this combination, the

transmitting station is called in the usual man-- her; and as the signals are heard. by the open-- ator at the receiving station, he places the telephone suficiently close to the microphone iii; that the signals will afiect the microphone to operate i223 and the microphone 'flhihin such a manner that any tone ,Which it may receive from the telephone will be amplified and impressed upon the microphone; In a similar manner resonator use is placedhetween the telephone E23 and the I microphone its insuch a manner that any tone which it will be impressed upon said the relayand cause the receiving instrument at tity. 1 I

In Fig. 3 is shown a further alternative which to provide an indication'of' the measured quanis an improvementon the form shown in Fig. 2 to the extent that it includes means for amplifying sound waves of the selected frequency representing' that of the signalswhich it is desiredto utilize, at the same time damping out other sounds T which might-tenclto introduce-erroneous results.

A receiving instnt use is connected in circuit with the relay mi and a microphone Hi2 i in a manner with the oonnectionof the corresponding parts shown in Fig. 2f A telephone Mii is arranged to produce an audible tone signal in .the e new-r, as that shown in the previous dras. Between the microphone I02 .and the telephone 8% is transposed a resonating chamher its tuned to the characteristic irequency of the s! tone. With this arrement it is found that a material degree ofamplifloation oi the desired tone is obtained without any correspoo incrln. the volume or other frequenci ec which may, be. present in the circuit.

in Fig. 4 is shown an application of the principle illustrated in Fla. 3 tothe traon and measurement of two dependent" sets or signals,

representing as many dependent measurements. The two systems may be character-med as system A and system B. System A includes a transmitamplifier W]. at the. n: H ttlng end, and at the receiving enda receiver tilt, amicrophone tile with a relay m for rendering the receiver sub 'Ject to the microphone and a resonator ill.

Similarly, the system B includes a-transmitter III. a control box M3 1 and a microphonT tit,

4 5 corres'po 5 boxes access its fiiicrophone.

The operation oithe system in this form isas follows: uponthe operator-at the receiving station dialing, or o irwise calling the unattended station at the'tr "tting point, both control automatically placed in service and the motors in the transmitting instrument s will begin to operate. vEach of the transmitterswill then define a series of impulses to the: magnitudes respectively measureolthereby, and these impulses-will be impressed tipon'the microphones i811 and ti l as so waves having characteristic tones. These sound waveowill too impressed upon the comso munication channel are as electric currents, and,

or course maybe carriedsimultaneously in the circuit without mutuai interference. The sound ating from the telephone 823 may then be a combination or the tones developed by the two ting instrument lot, a control her not, and an transmitting instruments, and these tones may come simultaneously or concurrently. This sound being lmpremed uponthe resonators iii and M8, will by them be resolved into its com.-

ponent tones, so that the microphone its will respend only to the signals developed by the transmitter lit-2. 'Kn' -this way the ireceiving instruments liitlantl lit} operate without interference to pdedjm'easurements "of the magnitudes originuily' determined by the transmitters vifliianrliflil." e

The termeand expressions which I have employed are as terms of description and not of tatlon; and I have no intention, in the useofsuc'h and expressions, of excluding any eqnivalentsjoi' the features shown and described or portions 2, but recognize that various modifications areble within the scop of the invention ced, V v

lii'claiin:

1. In a-teletering system for providing-at a index for translating said impulses into repre-' receiving station representations of values of a quantity measured at a remote transmitting station, the combination of normally inert means at said transmitting station for measuring an unlimited number of said values within a given range and creating in each of uniform time cycles a continuous audible signal of a duration corresponding to values of said quantity,-means for converting said audible signals into electrical impulses corresponding with said quantity values, relay means controlled from said receiving stasentations of said magnitudes bythe position of tion for bringing said transmitting and converting means into action, means at said receiving station whereby said impulses may be converted into scalar magnitudes representative of said values, and means at said transmitting station for terminating signal transmission at the end of a predetermined time.

2. In a telemetering system for providing at a receiving station representations of values of a quantity measured at a remote transmitting station, the combination of telephonicmeans at said receiving station and a communication means at said transmitting station for measuring an unlimited number of said values within a given range and creating in.each of uniform time cycles a continuous audible signal of a duration corresponding to values of said quantity, means for converting said audible signals into electrical impulses and impressing the latter upon said channel, relay means for bringing said transmitting and converting means into action, and other relay means responsive to flow of ringing current in said channel for controlling the first-mentioned relay means.

3. In a telemetering system for providing at a receiving station representations of values of a quantity measured at a remote transmitting station, the combination of telephonic means atsaid receiving station and a communication channel extending therefrom, normally inert means at. said transmitting station for measuring an unlimited number of said values within a given range and creating in each of uniform time cycles a continuous audible signal of a duration corresponding to values of said quantity, means for converting .said audible signals into electrical impulses and impressing the latter upon said channel, relay means for bringing said transmitting and'converting means into action, other relay means responsive to flow of ringing current in said channelfor controlling the first-mentioned relay means, and means at said receiving station including a scale and an channel extending therefrom, normally inert said index with respect to'said scale.

.- 4. In a telemetering system for providing at a receiving station representations of values .of a quantity measured at ,a remote transmitting station, the combination of telephonic means at said receiving station and a communication channel extending therefrom, normally inert means at said transmitting station for creating in each of uniform time cycles an audible signal of a duration corresponding to values of said quantity, means for converting said audible signals into electrical impulses and impressing the latter upon said channel, relaymeans- 5. In a telemetering" system for providing at a receiving station representations of values of a quantity measured at a rempte transmitting station, the combination of telephonic means at said receiving station and a communication channel extending therefrom, normally inert means at said transmitting station for measuring an unlimited number of said values within a given range, and creating in each of uniform time cycles a continuous audible signal of a duration corresponding to values of said quantity, means for converting said audible signals intoelectrical impulses and impressing the latter upon said channel, relay means for bringing said transmitting and converting means into action, timing means brought into action by said relay means for controlling ,the period of operation of said trans mitting means, other relay means responsive to flow of ringing current in said channel for controlling the first-mentioned relay means, and contact means controlled by said timing means for maintaining the latter in operation for a predeterminedperiod despite cessation of said ringing current and for thereafter terminating operation of said timing means. R I

FRANKLIN B. BRISTOL. 

